Field of the Disclosure
The present disclosure relates to a display device, and more particularly, to a flexible display. Although the present disclosure has a wide scope of applications, it is particularly suitable for preventing moisture penetration through a flexible substrate of the display device.
Description of the Background
With development of information society, demands for display devices displaying an image have been increased in various ways. In a field of the display devices, a large-sized cathode ray tube (CRT) has been rapidly replaced by a flat panel display (FPD) having advantages of a thin profile, light weight, and a large-sized screen. Examples of the flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) display, and an electrophoresis display (EPD).
An OLED display includes a plurality of self-emitting elements capable of emitting light and has advantages of a fast response time, a high emission efficiency, a high luminance and a wide viewing angle. In particular, the OLED display may use a flexible plastic substrate. In addition, the OLED display has advantages of a lower driving voltage, lower power consumption, and better color tone as compared to a plasma display panel or an inorganic electroluminescent display.
The OLED display may include a plurality of buffer layers on a flexible plastic substrate. The plurality of buffer layers blocks ions or impurities diffused from the plastic substrate underlying the buffer layers in a manufacturing process of the OLED display. Further, the plurality of buffer layers blocks the penetration of external moisture from the plastic substrate after manufacturing of the OLED display is completed, thereby preventing the degradation of thin film transistors and organic light emitting diodes.
However, the buffer layer affects the component adjacent to the buffer layer due to the properties of a material constituting the buffer layer, thereby degrading characteristics of the component. For example, the buffer layer may include silicon nitride (SiNx). When the thin film transistor includes an oxide semiconductor, hydrogen existing in silicon nitride of the buffer layer can be diffused and deteriorates electrical characteristics of the oxide semiconductor.